Statistical analysis of noise in towed streamer arrays

Towed arrays of hydrophones are commonly used in marine seismic to infer properties about the sea bottom. Normally, air guns are used as impulsive sources of pressure waves, and the hydrophone recordings are employed to estimate three dimensional maps of the geological layer structure of the subsurface sea bottom. In this paper, we present a statistical analysis of pure noise recordings, i.e., passive hydrophone recordings in the absence of impulsive sources. In particular, we show that a multitaper power spectral estimate of the noise processes yields a composite power law spectrum. Furthermore, on the basis of Parzen kernel estimates and higher-order moment analysis of the noise amplitudes, we deduce that the noise is slightly platykurtic (sub-Gaussian) and almost symmetric. These findings will have consequences for future noise reduction and signal detection algorithms.